The conventional North American Public Switched Telephone Network, or PSTN, has a frequency response range of 300 Hz to 3,400 Hz. The normal hearing range of humans is typically 30 Hz to 20,000 Hz. So the conventional telephone transmission system is unable to carry bright, high-frequency and deep, low-frequency tones.

But, somewhat surprisingly, because our ears are so used to hearing poor-quality audio over the telephone, our brains actually “fill in” the missing frequencies. As an example, the crisp “s” sound in the word “Christmas”. So in effect, the telephone audio often sounds better than it actually is to us.

Share:

Like this:

Related

Really, that is amazing, I did not know that. I use a JawBone with my iPhone, and rarely use the phone itself. And when in online meetings I wear a Logitech headset, which is much clearer than the Jawbone.

About...

PMO Director. These are my personal thoughts about software development, technology and related topics that interest me. In general, you will find a bias towards project management related issues and lots of talk about interacting with stakeholders or programmers. I try to present a technical view from a user's perspective. The views presented here on my professional and personal blog represent my own views and experiences and not those of my employer.